We're talking about the correlation between fat and puberty when the prof says "Anyone know any long distance sprinters?" or something like that. Cue silence, but then one guy hesitantly holds up his hand.
Prof looks at him and asks, "Does she menstruate?" Cue even more silence, but now we're all staring at the guy. He slowly nodded his head.
Near the end of class, Prof asks, "Why do they make scented tampons?" I mentally checked out after that.